1. Field of the Invention
The present invention relates to a check valve, and more particularly to a ball check valve that has features of filtering impurities and regulating simultaneously from a fluid flow through the check valve.
2. Description of Related Art
Check valves are generally employed to plumber systems when it is necessary to limit fluid flow in only one direction. Ball check valves use a ball as the valve member, which provides a precision and long lasting part at low cost.
With reference to FIG. 3, a conventional ball check valve 50 is suitable for being mounted in a conduit 60 and comprises a valve ball 51 and a valve cage 52 or retainer. The valve ball 51 is movably mounted and held in the valve cage 52.
The valve cage 52 is mounted in the conduit 60 and has a cage base 53 with multiple holding fingers 54. The cage base 53 is annular and has a top, a bottom and a central hole 55. The central hole 55 is defined completely through the cage base 53 and has a top inclined edge. The top inclined edge services as a valve seat 56 on which the valve ball 51 is abutted to close the check valve 50.
The holding fingers 54 are formed integrally from the top of the cage base 53 and are arranged in parallel with respect to each other. Each holding finger 54 has a distal end with an inward stop surface 57. Each inward stop surface 57 is inclined so that the valve ball 51 will be limited and held in the valve cage 53 when the check valve 50 is open.
However, the conventional ball check valve 50 only has one feature of limiting the fluid flow in the conduit 60 in one direction. The conventional ball check valve 50 does not have any feature of filtering and regulating the fluid flow. Therefore, the practical usage of the conventional ball check valve 50 is restrictive.
Furthermore, because the valve seat 56 is an inclined surface, a contact relationship between the valve ball 51 and the valve seat 56 is approximate to a surface contact when the valve ball 51 seats on the valve seat 56. The surface of the valve seat 56 is large and is easy to be contaminated by the impurities in the fluid flow. At such a state, the check valve 50 cannot be completely closed because the valve ball 51 cannot exactly contact with the valve seat 56. Leakage will occur between the valve ball 51 and the valve seat 56 through the central hole 55.
To overcome the shortcomings, the present invention provides an improved ball check valve to mitigate or obviate the aforementioned problems.